No Damage after Use of Heart-lung Machines

CABG surgery has been widely feared to cause “pump-related” damage to the cerebral cortex. To check whether there was a basis for the concern McKhann, a professor in the Department of Neurology at the John Hopkins University School of Medicine involved 380 individuals between 1997 and 2003. MecKhann led a non-randomized study comparing the cognitive abilities of on-pump CABG, off-pump CABG and nonsurgical patients with coronary artery disease and heart- healthy individuals. They were given a battery of standardized neuropsychological tests that were repeated three and 12 months later.

The study showed that on-pump CABG patients had no significant differences in their higher-level mental functions than the other groups tested. At the start of the study, subjects with coronary artery disease had overall lower performance than the heart-healthy group in several cognitive domains. But by three months, all groups had improved, which McKhann says was most likely due to familiarization with the testing procedures. Between three and 12 months, there were minimal changes in individual subjects for all groups, and no consistent differences between the CABG and off-pump patients were observed. “These results offer no evidence that the cognitive test performance of on-pump CABG patients differed from that of off-pump control groups with coronary artery disease over a one-year period,” McKhann said.

Test scores were sorted and combined into eight areas: verbal memory, visual memory, language, attention span, visuoconstruction, motor speed, psychomotor speed and executive function. Self-reporting of well-being was included in the study in the areas of memory, mental arithmetic, personality, and reading newspapers and books.